/*
 * RFC 1321 compliant MD5 implementation
 *
 * Copyright (C) 2001-2003	 Christophe Devine
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "md5.h"
#include <string.h>

#define GET_UINT32(n,b,i)				\
{							\
	(n) = ( (uint32_t) (b)[(i)] )			\
		| ( (uint32_t) (b)[(i) + 1] <<	8 )	\
		| ( (uint32_t) (b)[(i) + 2] << 16 )	\
		| ( (uint32_t) (b)[(i) + 3] << 24 );	\
}

#define PUT_UINT32(n,b,i)				\
{							\
	(b)[(i)	   ] = (unsigned char) ( (n)	   );	\
	(b)[(i) + 1] = (unsigned char) ( (n) >>	 8 );	\
	(b)[(i) + 2] = (unsigned char) ( (n) >> 16 );	\
	(b)[(i) + 3] = (unsigned char) ( (n) >> 24 );	\
}

void md5_start(md5_context * ctx)
{
	ctx->total[0] = 0;
	ctx->total[1] = 0;

	ctx->state[0] = 0x67452301;
	ctx->state[1] = 0xEFCDAB89;
	ctx->state[2] = 0x98BADCFE;
	ctx->state[3] = 0x10325476;
}

static void md5_process(md5_context * ctx, unsigned char data[64])
{
	uint32_t X[16], A, B, C, D;

	GET_UINT32(X[0], data, 0);
	GET_UINT32(X[1], data, 4);
	GET_UINT32(X[2], data, 8);
	GET_UINT32(X[3], data, 12);
	GET_UINT32(X[4], data, 16);
	GET_UINT32(X[5], data, 20);
	GET_UINT32(X[6], data, 24);
	GET_UINT32(X[7], data, 28);
	GET_UINT32(X[8], data, 32);
	GET_UINT32(X[9], data, 36);
	GET_UINT32(X[10], data, 40);
	GET_UINT32(X[11], data, 44);
	GET_UINT32(X[12], data, 48);
	GET_UINT32(X[13], data, 52);
	GET_UINT32(X[14], data, 56);
	GET_UINT32(X[15], data, 60);

#define S(x,n) 	((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define P(a,b,c,d,k,s,t)  do { a += F(b,c,d) + X[k] + t; a = S(a,s) + b; } while(0)

	A = ctx->state[0];
	B = ctx->state[1];
	C = ctx->state[2];
	D = ctx->state[3];

#define F(x,y,z) (z ^ (x & (y ^ z)))
	P(A, B, C, D, 0, 7, 0xD76AA478);
	P(D, A, B, C, 1, 12, 0xE8C7B756);
	P(C, D, A, B, 2, 17, 0x242070DB);
	P(B, C, D, A, 3, 22, 0xC1BDCEEE);
	P(A, B, C, D, 4, 7, 0xF57C0FAF);
	P(D, A, B, C, 5, 12, 0x4787C62A);
	P(C, D, A, B, 6, 17, 0xA8304613);
	P(B, C, D, A, 7, 22, 0xFD469501);
	P(A, B, C, D, 8, 7, 0x698098D8);
	P(D, A, B, C, 9, 12, 0x8B44F7AF);
	P(C, D, A, B, 10, 17, 0xFFFF5BB1);
	P(B, C, D, A, 11, 22, 0x895CD7BE);
	P(A, B, C, D, 12, 7, 0x6B901122);
	P(D, A, B, C, 13, 12, 0xFD987193);
	P(C, D, A, B, 14, 17, 0xA679438E);
	P(B, C, D, A, 15, 22, 0x49B40821);
#undef F

#define F(x,y,z) (y ^ (z & (x ^ y)))
	P(A, B, C, D, 1, 5, 0xF61E2562);
	P(D, A, B, C, 6, 9, 0xC040B340);
	P(C, D, A, B, 11, 14, 0x265E5A51);
	P(B, C, D, A, 0, 20, 0xE9B6C7AA);
	P(A, B, C, D, 5, 5, 0xD62F105D);
	P(D, A, B, C, 10, 9, 0x02441453);
	P(C, D, A, B, 15, 14, 0xD8A1E681);
	P(B, C, D, A, 4, 20, 0xE7D3FBC8);
	P(A, B, C, D, 9, 5, 0x21E1CDE6);
	P(D, A, B, C, 14, 9, 0xC33707D6);
	P(C, D, A, B, 3, 14, 0xF4D50D87);
	P(B, C, D, A, 8, 20, 0x455A14ED);
	P(A, B, C, D, 13, 5, 0xA9E3E905);
	P(D, A, B, C, 2, 9, 0xFCEFA3F8);
	P(C, D, A, B, 7, 14, 0x676F02D9);
	P(B, C, D, A, 12, 20, 0x8D2A4C8A);
#undef F

#define F(x,y,z) (x ^ y ^ z)
	P(A, B, C, D, 5, 4, 0xFFFA3942);
	P(D, A, B, C, 8, 11, 0x8771F681);
	P(C, D, A, B, 11, 16, 0x6D9D6122);
	P(B, C, D, A, 14, 23, 0xFDE5380C);
	P(A, B, C, D, 1, 4, 0xA4BEEA44);
	P(D, A, B, C, 4, 11, 0x4BDECFA9);
	P(C, D, A, B, 7, 16, 0xF6BB4B60);
	P(B, C, D, A, 10, 23, 0xBEBFBC70);
	P(A, B, C, D, 13, 4, 0x289B7EC6);
	P(D, A, B, C, 0, 11, 0xEAA127FA);
	P(C, D, A, B, 3, 16, 0xD4EF3085);
	P(B, C, D, A, 6, 23, 0x04881D05);
	P(A, B, C, D, 9, 4, 0xD9D4D039);
	P(D, A, B, C, 12, 11, 0xE6DB99E5);
	P(C, D, A, B, 15, 16, 0x1FA27CF8);
	P(B, C, D, A, 2, 23, 0xC4AC5665);
#undef F

#define F(x,y,z) (y ^ (x | ~z))
	P(A, B, C, D, 0, 6, 0xF4292244);
	P(D, A, B, C, 7, 10, 0x432AFF97);
	P(C, D, A, B, 14, 15, 0xAB9423A7);
	P(B, C, D, A, 5, 21, 0xFC93A039);
	P(A, B, C, D, 12, 6, 0x655B59C3);
	P(D, A, B, C, 3, 10, 0x8F0CCC92);
	P(C, D, A, B, 10, 15, 0xFFEFF47D);
	P(B, C, D, A, 1, 21, 0x85845DD1);
	P(A, B, C, D, 8, 6, 0x6FA87E4F);
	P(D, A, B, C, 15, 10, 0xFE2CE6E0);
	P(C, D, A, B, 6, 15, 0xA3014314);
	P(B, C, D, A, 13, 21, 0x4E0811A1);
	P(A, B, C, D, 4, 6, 0xF7537E82);
	P(D, A, B, C, 11, 10, 0xBD3AF235);
	P(C, D, A, B, 2, 15, 0x2AD7D2BB);
	P(B, C, D, A, 9, 21, 0xEB86D391);
#undef F

	ctx->state[0] += A;
	ctx->state[1] += B;
	ctx->state[2] += C;
	ctx->state[3] += D;
}

void md5_update(md5_context * ctx, const void *input, size_t length)
{
	uint32_t left, fill, len;

	if (!length)
		return;

	left = ctx->total[0] & 0x3F;
	fill = 64 - left;

	len = length;
#if UINT32_MAX < SIZE_MAX
	if (len < length)
		ctx->total[1] += (length >> 32);
#endif

	ctx->total[0] += len;
	ctx->total[0] &= 0xFFFFFFFF;
	if (ctx->total[0] < len)
		ctx->total[1]++;

	if (left && length >= fill) {
		memcpy((void *) (ctx->buffer + left), (void *) input, fill);
		md5_process(ctx, ctx->buffer);
		length -= fill;
		input = (char *)input + fill;
		left = 0;
	}

	while (length >= 64) {
		md5_process(ctx, (unsigned char *)input);
		length -= 64;
		input = (char *)input + 64;
	}

	if (length) {
		memcpy((ctx->buffer + left), input, length);
	}
}

static unsigned char md5_padding[64] = {
     0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

inline void md5_get(md5_context *ctx, unsigned char digest[16])
{
	PUT_UINT32(ctx->state[0], digest, 0);
	PUT_UINT32(ctx->state[1], digest, 4);
	PUT_UINT32(ctx->state[2], digest, 8);
	PUT_UINT32(ctx->state[3], digest, 12);
}

void md5_finish(md5_context * ctx, unsigned char digest[16])
{
	uint32_t last, padn;
	uint32_t high, low;
	unsigned char msglen[8];

	high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
	low = (ctx->total[0] << 3);

	PUT_UINT32(low, msglen, 0);
	PUT_UINT32(high, msglen, 4);

	last = ctx->total[0] & 0x3F;
	padn = (last < 56) ? (56 - last) : (120 - last);

	md5_update(ctx, md5_padding, padn);
	md5_update(ctx, msglen, 8);

	md5_get(ctx, digest);
}

void md5_checksum(unsigned char digest[16], const void *input, size_t length)
{
	md5_context ctx;

	md5_start(&ctx);
	md5_update(&ctx, input, length);
	md5_finish(&ctx, digest);
}


#ifdef TEST_MD5

#include <stdlib.h>
#include <stdio.h>

/*
 * those are the standard RFC 1321 test vectors
 */

static char *msg[] = {
	"",
	"a",
	"abc",
	"message digest",
	"abcdefghijklmnopqrstuvwxyz",
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
	"12345678901234567890123456789012345678901234567890123456789012345678901234567890"
};

static char *val[] = {
	"d41d8cd98f00b204e9800998ecf8427e",
	"0cc175b9c0f1b6a831c399e269772661",
	"900150983cd24fb0d6963f7d28e17f72",
	"f96b697d7cb7938d525a2f31aaf161d0",
	"c3fcd3d76192e4007dfb496cca67e13b",
	"d174ab98d277d9f5a5611c2c9f419d9f",
	"57edf4a22be3c955ac49da2e2107b67a"
};

int main(int argc, char *argv[])
{
	FILE *f;
	int i, j;
	char output[33];
	md5_context ctx;
	unsigned char buf[1000];
	unsigned char md5sum[16];

	if (argc < 2)
	{
		printf("\n MD5 Validation Tests:\n\n");

		for (i = 0; i < 7; i++) {
			printf(" Test %d ", i + 1);

			md5_start(&ctx);
			md5_update(&ctx, (unsigned char *) msg[i], strlen(msg[i]));
			md5_finish(&ctx, md5sum);

			for (j = 0; j < 16; j++) {
				sprintf(output + j * 2, "%02x", md5sum[j]);
			}

			if (memcmp(output, val[i], 32)) {
				printf("failed!\n");
				return 1;
			}

			printf("passed.\n");
		}
		printf("\n");
	}
	else
	{
		if (!(f = fopen(argv[1], "rb"))) {
			perror("fopen");
			return 1;
		}

		md5_start(&ctx);

		while ((i = fread(buf, 1, sizeof(buf), f)) > 0) {
			md5_update(&ctx, buf, i);
		}

		md5_finish(&ctx, md5sum);

		for (j = 0; j < 16; j++) {
			printf("%02x", md5sum[j]);
		}

		printf("  %s\n", argv[1]);
	}

	return 0;
}

#endif
